Vehicles may be equipped with a brake system configured to supply hydraulic fluid to brakes at a plurality of wheels. This is known as a hydraulic brake system. Hydraulic brake systems typically include a vacuum booster coupled to a brake pedal to provide an additional boost of force to assist in the application of the hydraulic fluid to the brakes in response to brake pedal displacement. An internal combustion engine may provide as the source of vacuum to the vacuum booster.
Active vacuum boosters are a type of vacuum boosters that include a valve or other controllable mechanism to provide the booster with a vacuum force even without sufficient brake pedal displacement. A vacuum pump may provide as a source of vacuum to the active vacuum booster. Hybrid electric vehicles (HEVs) and battery electric vehicles (BEVs) may also include regenerative brake systems in which kinetic energy from the wheels is absorbed through the powertrain of the vehicle and stored in a high voltage battery. The hydraulic brake system and regenerative brake system in HEVs and BEVs are coordinated to supply desired braking forces to the wheels of the vehicles.